Hohmann Transfer to Jupiter

[Achilles001]

Hi,

I'm looking for a basic xyz orbit file for a direct hohmann transfer from Earth to Jupiter. Does anyone have one or know where I could find one? Any epoch is fine.
Thanks

[selden]

JAQAR's SwingBy can be used to generate them for any epoch you want.

http://www.jaqar.com/swingby.html

It will generate xyzv data in its .tf files if you select the menu Options/ "Write Trajectory Files of best solution". You'll have to edit them into Celestia's format and specify
OrbitFrame { EquatorJ2000 { Center "Sol" } }
in the SSC file.

[Achilles001]

Thanks. I'm aware of the format for Celestia's scc files, but I don't know how to generate them. I just want a plain transfer orbit with no object or texture attached. Do I need an scc and an xyz file? Can they be the same thing?

[selden]

Achilles001,

An SSC file is what Celestia uses to define an object in space.
An xyz file is one of several ways to specify a trajectory within an SSC file.

As an example, you might take a look at the SSC file used by Celestia to define the Galileo probe. Its xyz trajectory defines the rather complex path that it took to get to Jupiter.
By specifying a different xyz file, you could cause Celestia to draw it flying directly to Jupiter instead of going past several other planets.

In Celestia v1.5.1, both files are in the \data\ folder.
Galileo's definition is one of several entries in spacecraft.ssc
Its xyz trajectory is in the file galileo.xyz
xyz files are plain text files. You can use any editor you want to change them.
You could, for example, delete all but the first and last entries in galileo.xyz
Then the probe would travel straight from the Earth to Jupiter in Celestia.
That trajectory wouldn't be physically possible, of course.

[Achilles001]

Okay,

I took the existing galileo xyz file and switched the data with the newly generated transfer data from the swingby program. The transfer orbit shows up correctly in celestia at the right place and time, but the galileo spacecraft model doesn't follow the orbit. It just sits in place from launch at Earth while everything thing else moves along. I think either the epoch may be off or I've incorrectly edited the tf file info. There are seven columns of data in the tf file: MJD2000, X, Y, Z, Vx, Vy, Vz, and yet the existing xyz file for galileo only had 4 columns. I assumed the first four columns from the tf data corresponded to the first four columns of the existing data in the galileo xyz file. Perhaps I need to include some sort of velocity information, since the galileo model isn't moving?

The tf data looks like this:

MJD2000 X(KM) Y(KM) Z(KM) VX(KM/S) VY(KM/S) VZ(KM/S)
--------------------------------------------------------------------------------------------------------------------------
6590.5000000000000 -65224304.2005058154 121034757.5063510686 52462501.3198883682 -34.0811684905 -17.9544208570 -5.4507478063
6601.3100000000004 -95676512.4409918338 102166784.6530069858 46448636.0960077345 -30.9338769721 -22.3216311915 -7.3860153073
6612.1200000000008 -122712943.5666394234 79638252.7608499825 38771203.4155539423 -26.8456690908 -25.7359028243 -8.9857324807
6622.9300000000012 -145693103.2066174750 54453275.0475903675 29802473.8614131026 -22.3371844129 -28.0022707670 -10.1432476406
6633.7400000000016 -164458152.4464470150 27667037.3704033121 19961054.1587496772 -17.8869335527 -29.1940049248 -10.8627179863
6644.5500000000020 -179221486.7824269530 184500.0427343644 9624584.2178489249 -13.8038131142 -29.5362116587 -11.2187922007
6655.3600000000024 -190400985.1096714140 -27320550.6479469612 -911964.2419135295 -10.2235125753 -29.2823199491 -11.3068115515
6666.1700000000028 -198481561.6657031180 -54395629.6141217053 -11439615.8063793015 -7.1644778670 -28.6464234169 -11.2124442972


but the original galileo xyz data looks just looks like this:

2447818.615972 134114700.2612462193 64912642.6984842718 39861.799941
2447819.615972 133153386.7785827518 66969511.3118158504 237125.784089
2447820.615972 132137795.3581911474 69024279.8844281882 418499.867572
2447821.615972 131079666.1268854141 71061806.8872888833 596914.157647
2447822.615972 129980969.5350295901 73079633.1750401706 773878.750115
2447823.615972 128842629.4996801615 75076509.4863193184 949883.412645
2447824.615972 127665267.5453006476 77051533.4647789001 1125130.045395

And the Galileo scc data looks like this:

"Galileo" "Sol"
{
Class "spacecraft"
Mesh "galileo.3ds"
Radius 0.01

InfoURL "http://galileo.jpl.nasa.gov"

Beginning "2018 1 16 02:47" # Launch
Ending "2021 9 21 10:44" # Crash into Jupiter

SampledOrbit "galileo.xyz"
EllipticalOrbit
{
Period 1081
SemiMajorAxis 493673400
Eccentricity 0.831774
Inclination 4.213
AscendingNode 59.562
ArgOfPericenter 97.224
TrueAnomaly 0
}
OrbitFrame { EquatorJ2000 { Center "Sol" } }
Orientation [ 90 0 1 0 ]
Albedo 0.50

[selden]

You need to be running a pre-release of Celestia v1.6 in order to use an xyzv file.
For v1.5.1, you'll have to delete the last three columns of numbers (xv,yv,zv)

For details, please read the Celestia Wikibook at
http://en.wikibooks.org/wiki/Celestia/T ... mpledOrbit

[Achilles001]

I finally got it to work. Thanks so much for the help.

[Guckytos]

JAQAR's SwingBy can be used to generate them for any epoch you want.

http://www.jaqar.com/swingby.html

It will generate xyzv data in its .tf files if you select the menu Options/ "Write Trajectory Files of best solution". You'll have to edit them into Celestia's format and specify
OrbitFrame { EquatorJ2000 { Center "Sol" } }
in the SSC file.

Hi Selden,

why don't you add a link for this site to the "Useful Helpers Repository (Programs/Spreadsheets etc.)" thread?

Sounds like a prime candidate for useful helper for me.

Best regards,

Guckytos

[selden]

I've added it.